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本文研究了一些直接影响单晶 Ni 基高温合金持久强度的因素。原始晶界和由机械加工引起的再结晶对性能的危害极大。在经高温持久试验后的单晶中,往往形成亚结构和微孪晶。单晶合金的[001]方向平行应力轴时,持久性能最佳。当[001]方向与应力轴夹角大于10°时,持久强度大幅度下降。单晶合金中碳化物的含量越多,尺寸越大,对持久性能损害越大。初生γ′和共晶相区是单晶合金中的低强度区域,应通过固溶热处理消除。单晶高温合金经组织结构和晶体取向的一系列优化后,持久强度比普通铸造和定向凝固合金显著提高。
This article studies some factors that have a direct impact on the long-term strength of single crystal Ni-based superalloys. The original grain boundaries and the recrystallization caused by machining are very harmful to the performance. Sub-structures and micro-twins are often formed in single crystals after long-term high temperature tests. Single crystal alloy [001] direction parallel to the stress axis, the best long-lasting performance. When the angle between the [001] direction and the stress axis is more than 10 °, the lasting strength decreases sharply. The greater the amount of carbide in the single crystal alloy, the larger the size, the harder it is to the permanent properties. The nascent γ ’and eutectic phase regions are low-intensity regions in single crystal alloys that should be eliminated by solution heat treatment. After a series of optimization of the structure and crystal orientation of the single crystal superalloy, the lasting strength is significantly higher than that of the ordinary casting and the directional solidification alloy.